The present invention relates to a method of joining timber elements with other construction parts by a clamping bolt put through a hole in the timber element. It is a well known phenomenon that both new and aged timber may shrink in its cross plane and that it may be necessary from time to time, therefore, to tighten up the bolt joints.
This, of course, amounts to a general problem, but the problem is particularly pronounced in such constructions, in which the bolt joints are desired to be protected against wanton destruction, as in such cases it is not even possible to tighten up the bolts or nuts. A bolt or nut protection of this type is used extensively in public park and playground equipment, e.g. benches and playing devices, which may include timber elements, to which other timber elements or parts of other materials are joined by bolting. It is at this place sufficient to mention that prior attempts to solve the said problem have generally failed.
It is the purpose of the invention to provide a method, whereby the bolt joint is preparable such that it will not have to be tightened up later on.
The invention is based on the consideration that with ordinary simple bolt joints of or between timber portions the joined portions should not be held together so as to be locked against mutual rotation about the bolt by virtue of the tightening force of the single bolt, inasfar as a desired non-rotatability of the portions or element will normally always be achieved by the use of an extra bolt joint spaced from the first one or by some other type of additional connection between the bolted together portions or elements. Thus, what should be ensured is that the bolted together elements cannot "slop" or get mutually twisted as the timber element or elements shrink.